import type { Payment } from '../plugin/types/payments'
import type { PaymentProvider } from '../plugin/types/index'
import type { Payload } from 'payload'
import { createSingleton } from '../plugin/singleton'
import type { createMollieClient, MollieClient } from '@mollie/api-client'
import {
  webhookResponses,
  findPaymentByProviderId,
  updatePaymentStatus,
  updateInvoiceOnPaymentSuccess,
  handleWebhookError,
  validateProductionUrl
} from './utils'
import { formatAmountForProvider, isValidAmount, isValidCurrencyCode } from './currency'

const symbol = Symbol('mollie')
export type MollieProviderConfig = Parameters<typeof createMollieClient>[0]

/**
 * Type-safe mapping of Mollie payment status to internal status
 */
function mapMollieStatusToPaymentStatus(mollieStatus: string): Payment['status'] {
  // Define known Mollie statuses for type safety
  const mollieStatusMap: Record<string, Payment['status']> = {
    'paid': 'succeeded',
    'failed': 'failed',
    'canceled': 'canceled',
    'expired': 'canceled',
    'pending': 'pending',
    'open': 'pending',
    'authorized': 'pending',
  }

  return mollieStatusMap[mollieStatus] || 'processing'
}

export const mollieProvider = (mollieConfig: MollieProviderConfig & {
  webhookUrl?: string
  redirectUrl?: string
}) => {
  // Validate required configuration at initialization
  if (!mollieConfig.apiKey) {
    throw new Error('Mollie API key is required')
  }

  const singleton = createSingleton<MollieClient>(symbol)
  return {
    key: 'mollie',
    onConfig: (config, pluginConfig) => {
      // Always register Mollie webhook since it doesn't require a separate webhook secret
      // Mollie validates webhooks through payment ID verification
      config.endpoints = [
        ...(config.endpoints || []),
        {
          path: '/payload-billing/mollie/webhook',
          method: 'post',
          handler: async (req) => {
            try {
              const payload = req.payload
              const mollieClient = singleton.get(payload)

              // Parse the webhook body to get the Mollie payment ID
              if (!req.text) {
                return webhookResponses.missingBody()
              }
              const body = await req.text()
              if (!body || !body.startsWith('id=')) {
                return webhookResponses.invalidPayload()
              }

              const molliePaymentId = body.slice(3) // Remove 'id=' prefix

              // Fetch the payment details from Mollie
              const molliePayment = await mollieClient.payments.get(molliePaymentId)

              // Find the corresponding payment in our database
              const payment = await findPaymentByProviderId(payload, molliePaymentId, pluginConfig)

              if (!payment) {
                return webhookResponses.paymentNotFound()
              }

              // Map Mollie status to our status using proper type-safe mapping
              const status = mapMollieStatusToPaymentStatus(molliePayment.status)

              // Update the payment status and provider data
              const updateSuccess = await updatePaymentStatus(
                payload,
                payment.id,
                status,
                molliePayment.toPlainObject(),
                pluginConfig
              )

              // If payment is successful and update succeeded, update the invoice
              if (status === 'succeeded' && updateSuccess) {
                await updateInvoiceOnPaymentSuccess(payload, payment, pluginConfig)
              } else if (!updateSuccess) {
                console.warn(`[Mollie Webhook] Failed to update payment ${payment.id}, skipping invoice update`)
              }

              return webhookResponses.success()
            } catch (error) {
              return handleWebhookError('Mollie', error)
            }
          }
        }
      ]
    },
    onInit: async (payload: Payload) => {
      const createMollieClient = (await import('@mollie/api-client')).default
      const mollieClient = createMollieClient(mollieConfig)
      singleton.set(payload, mollieClient)
    },
    initPayment: async (payload, payment) => {
      // Validate required fields
      if (!payment.amount) {
        throw new Error('Amount is required')
      }
      if (!payment.currency) {
        throw new Error('Currency is required')
      }

      // Validate amount
      if (!isValidAmount(payment.amount)) {
        throw new Error('Invalid amount: must be a positive integer within reasonable limits')
      }

      // Validate currency code
      if (!isValidCurrencyCode(payment.currency)) {
        throw new Error('Invalid currency: must be a 3-letter ISO code')
      }

      // Setup URLs with development defaults
      const isProduction = process.env.NODE_ENV === 'production'
      const redirectUrl = mollieConfig.redirectUrl ||
        (!isProduction ? 'https://localhost:3000/payment/success' : undefined)
      const webhookUrl = mollieConfig.webhookUrl ||
        `${process.env.PAYLOAD_PUBLIC_SERVER_URL || (!isProduction ? 'https://localhost:3000' : '')}/api/payload-billing/mollie/webhook`

      // Validate URLs for production
      validateProductionUrl(redirectUrl, 'Redirect')
      validateProductionUrl(webhookUrl, 'Webhook')

      const molliePayment = await singleton.get(payload).payments.create({
        amount: {
          value: formatAmountForProvider(payment.amount, payment.currency),
          currency: payment.currency.toUpperCase()
        },
        description: payment.description || '',
        redirectUrl,
        webhookUrl,
      });
      payment.providerId = molliePayment.id
      payment.providerData = molliePayment.toPlainObject()
      return payment
    },
  } satisfies PaymentProvider
}